1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
|
// SPDX-License-Identifier: GPL-2.0-only
/*
* Input driver for resistor ladder connected on ADC
*
* Copyright (c) 2016 Alexandre Belloni
*/
#include <linux/err.h>
#include <linux/iio/consumer.h>
#include <linux/iio/types.h>
#include <linux/input.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/property.h>
#include <linux/slab.h>
struct adc_keys_button {
u32 voltage;
u32 keycode;
};
struct adc_keys_state {
struct iio_channel *channel;
u32 num_keys;
u32 last_key;
u32 keyup_voltage;
const struct adc_keys_button *map;
};
static void adc_keys_poll(struct input_dev *input)
{
struct adc_keys_state *st = input_get_drvdata(input);
int i, value, ret;
u32 diff, closest = 0xffffffff;
int keycode = 0;
ret = iio_read_channel_processed(st->channel, &value);
if (unlikely(ret < 0)) {
/* Forcibly release key if any was pressed */
value = st->keyup_voltage;
} else {
for (i = 0; i < st->num_keys; i++) {
diff = abs(st->map[i].voltage - value);
if (diff < closest) {
closest = diff;
keycode = st->map[i].keycode;
}
}
}
if (abs(st->keyup_voltage - value) < closest)
keycode = 0;
if (st->last_key && st->last_key != keycode)
input_report_key(input, st->last_key, 0);
if (keycode)
input_report_key(input, keycode, 1);
input_sync(input);
st->last_key = keycode;
}
static int adc_keys_load_keymap(struct device *dev, struct adc_keys_state *st)
{
struct adc_keys_button *map;
struct fwnode_handle *child;
int i;
st->num_keys = device_get_child_node_count(dev);
if (st->num_keys == 0) {
dev_err(dev, "keymap is missing\n");
return -EINVAL;
}
map = devm_kmalloc_array(dev, st->num_keys, sizeof(*map), GFP_KERNEL);
if (!map)
return -ENOMEM;
i = 0;
device_for_each_child_node(dev, child) {
if (fwnode_property_read_u32(child, "press-threshold-microvolt",
&map[i].voltage)) {
dev_err(dev, "Key with invalid or missing voltage\n");
fwnode_handle_put(child);
return -EINVAL;
}
map[i].voltage /= 1000;
if (fwnode_property_read_u32(child, "linux,code",
&map[i].keycode)) {
dev_err(dev, "Key with invalid or missing linux,code\n");
fwnode_handle_put(child);
return -EINVAL;
}
i++;
}
st->map = map;
return 0;
}
static int adc_keys_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct adc_keys_state *st;
struct input_dev *input;
enum iio_chan_type type;
int i, value;
int error;
st = devm_kzalloc(dev, sizeof(*st), GFP_KERNEL);
if (!st)
return -ENOMEM;
st->channel = devm_iio_channel_get(dev, "buttons");
if (IS_ERR(st->channel))
return PTR_ERR(st->channel);
if (!st->channel->indio_dev)
return -ENXIO;
error = iio_get_channel_type(st->channel, &type);
if (error < 0)
return error;
if (type != IIO_VOLTAGE) {
dev_err(dev, "Incompatible channel type %d\n", type);
return -EINVAL;
}
if (device_property_read_u32(dev, "keyup-threshold-microvolt",
&st->keyup_voltage)) {
dev_err(dev, "Invalid or missing keyup voltage\n");
return -EINVAL;
}
st->keyup_voltage /= 1000;
error = adc_keys_load_keymap(dev, st);
if (error)
return error;
input = devm_input_allocate_device(dev);
if (!input) {
dev_err(dev, "failed to allocate input device\n");
return -ENOMEM;
}
input_set_drvdata(input, st);
input->name = pdev->name;
input->phys = "adc-keys/input0";
input->id.bustype = BUS_HOST;
input->id.vendor = 0x0001;
input->id.product = 0x0001;
input->id.version = 0x0100;
__set_bit(EV_KEY, input->evbit);
for (i = 0; i < st->num_keys; i++)
__set_bit(st->map[i].keycode, input->keybit);
if (device_property_read_bool(dev, "autorepeat"))
__set_bit(EV_REP, input->evbit);
error = input_setup_polling(input, adc_keys_poll);
if (error) {
dev_err(dev, "Unable to set up polling: %d\n", error);
return error;
}
if (!device_property_read_u32(dev, "poll-interval", &value))
input_set_poll_interval(input, value);
error = input_register_device(input);
if (error) {
dev_err(dev, "Unable to register input device: %d\n", error);
return error;
}
return 0;
}
#ifdef CONFIG_OF
static const struct of_device_id adc_keys_of_match[] = {
{ .compatible = "adc-keys", },
{ }
};
MODULE_DEVICE_TABLE(of, adc_keys_of_match);
#endif
static struct platform_driver adc_keys_driver = {
.driver = {
.name = "adc_keys",
.of_match_table = of_match_ptr(adc_keys_of_match),
},
.probe = adc_keys_probe,
};
module_platform_driver(adc_keys_driver);
MODULE_AUTHOR("Alexandre Belloni <alexandre.belloni@free-electrons.com>");
MODULE_DESCRIPTION("Input driver for resistor ladder connected on ADC");
MODULE_LICENSE("GPL v2");
|
